1. Field of the Invention
This invention relates generally to a head mounted visual display for simulation and training that allows the user to see high quality, real time computer generated images and a see-through view of the real surrounding world. Specifically, the invention relates to a helmet mounted display that has a CRT visual image that is collimated, of high resolution and image quality with improved optical features including high light transmissivity, anti-luning, and a wide, instantaneous field of view (80.degree.) for enhanced realism.
2. Description of the Prior Art
The use of visual displays to provide real time, digitally generated images on a cathode ray tube (CRT) or liquid crystal display (LCD) for simulation and training purposes is known in the art. In recent years, a variety of helmet mounted visual displays have been provided. Aircraft cockpit heads up displays (HUD) and other types of helmet mounted optic systems for use in aircraft by pilots for target acquisition and other purposes are known.
U.S. Pat. No. 3,205,303, issued Sep. 7, 1965 to Bradley, shows a remotely controlled remote viewing system, a portion of which is attached to a helmet. U.S. Pat. No. 3,833,300, issued to Sep. 3, 1974 to Rymes, shows a three-dimensional weapon site using a helmet and visor. U.S. Pat. No. 4,001,499, issued Jan. 4, 1977 to Dowell, shows a display system used in an aircraft. A helmet mounted head-up display is shown in U.S. Pat. No. 4,153,913, issued May 8, 1979 to Swift. U.S. Pat. No. 4,761,056, issued Aug. 2, 1988 to Evans et al., shows a compact helmet mounted display. A fibre optic coupled helmet mounted display system is shown in U.S. Pat. No. 4,743,200, issued May 10, 1988 to Welch and LaRussa. U.S. Pat. No. 5,143,521, issued Jul. 28, 1992 to Lacroix et al., shows a wide-angle display device for a compact simulator. A helmet mounted area of interest display is shown in U.S. Pat. No. 5,320,534, issued Jun. 14, 1994 to Thomas. U.S. Pat. No. 5,348,477, issued Sep. 20, 1990 to Welch et al., shows a high definition television head mounted display unit.
One of the great drawbacks of current helmet mounted displays for simulation and training is that the visual display device itself optically blocks the user from observing the real world environment surrounding the user, which greatly limits the user's interaction with real world objects such as an aircraft cockpit, aircraft cockpit instrumentation and synthetic flight training controls. For example, a high level flight simulator has a complete realistic cockpit, including instrumentation, stick and throttle controls, gyro and navigational displays. If the user's helmet mounted display blocks the view of the surrounding cockpit, then the cockpit instrumentation, controls and other displays are not usable. Conversely, computer generated images of out-of-the-window scenes in real time are necessary for realistic training. Large video visual displays often have expensive, heavy glass mirrors or reflective surfaces and costly projectors with limited lumen capabilities. With the present invention, the user can view real time computer generated images or the actual environment while the helmet is in place on the user's head.
Other drawbacks of prior art helmet mounted displays are the poor visual resolution and the size and weight of the display components which often restrict freedom of movement of the user's head, reducing comfort and realism. Since the helmet or head mounted displays require a wire connection to the image generator, in the past, picture quality is greatly diminished as a function of the length of the wire distance between the helmet and the image generator.
The present invention overcomes problems found in current head and helmet mounted systems by providing a high quality video optic display that allows real world see-through with high light transmission factors for increased optical clarity, a collimated stereoscopic computer generated image view and improved signal amplification and other optic improvements.